Human and other mammalian stem cells including embryonic stem cells (hESCs and ESCs), which are pluripotent cells derived from pre-implantation embryos, have enormous potential as predicative models of early development or for cell replacement therapies (Draper et al., 2004, Stem Cells & Devel. 13:325-336). Because hESCs show remarkable sensitivity towards environmental influences, their continuous undifferentiated growth has been a major challenge undermining widespread use of hESCs in many applications. Currently, sustained hESC cultures still require naturally-derived cell substrates, such as mouse or human embryonic fibroblast cells, MATRIGEL, laminin, or fibronectin (Draper et al. 2004; Stojkovic et al., 2005, Stem Cells 23:306-314; Xu et al., 2001, Nat. Biotech. 19:971-974; Mallon et al., 2006, Int. J. Biochem. Cell Biol. 38:1063-1075; Amit et al., 2004, Biol. Repro. 70:837-845; Amit et al., 2003, Biol. Repro. 68:2150-2156; Skottman et al., 2006, Reproduction 132:691-698; Thomson et al., Science 282:1145-1147; Ellerstrom et al., 2006, Stem Cells 24:2170-2176; Xu et al., 2001, Nat. Biotechnol 19:971-974; Cheon et al., 2006, Biol. Reprod. 74:611; Beattie et al., 2005, Stem Cells 23:489-495).
However, xenogenic culture matrices are associated with several shortcomings. While co-culture systems with fibroblasts complicate direct studies of self-renewal and/or differentiation mechanisms of hESCs, cell substrates based on MATRIGEL and other naturally derived matrices show batch-to-batch inconstancies and may be prone to contaminations. To address these challenges, synthetic polymers have been proposed as cell culture substrates of hESC, because of their well-defined and reproducible fabrication, but have not yet been established for long-term hESC cultures.
As such, what are needed are compositions and methods that provide an environment for growth and maintenance of embryonic stem cells. The establishment of defined microenvironments for stem cell culture addresses a major issue of human embryonic stem cell research, and will provide embryonic stem cells useful in, for example, research purposes and potential clinical treatments of diseases.